Vehicle frames are often supported by axle housings that partially enclose axles on which wheels or other ground engaging members are mounted. Inertial forces exerted through the vehicle frames act on the axle housings in a first direction while the ground engaging members which are used to propel the vehicles exert reaction forces on the axle housings in a second, opposed direction. Of course, if the subject vehicle is pushing or drawing a load, the forces acting on the axle housing increase substantially beyond the inertial and reaction forces and must also be operationally accommodated by the axle housing.
Heavy-duty work vehicles have, in the past, typically used cast axle housings with the mounting brackets for connection to the frames being cast integrally with the axle housing. More recently, however, fabricated axle housings have come into wider use in certain applications, necessitating development of axle housing mounting brackets which can be attached to the fabricated axle housings to uniformly distribute forces between the vehicle's frame and axle housing.
One mounting bracket that has been successfully used includes an upper portion which is welded on the axle housing's neutral axis and a heavy, loose flat plate that is bolted to the bottom of the axle housing. Such loose, flat plate is massive and difficult to manipulate during its assembly. Preloads in bolts holding the frame to the mounting bracket are, in the aforementioned design, resisted by the housing. As such, substantial residual stresses are introduced into the housing which make it prone to buckling when external forces are introduced. Moreover, such design does not resist fore-aft motion in the lower half of the housing making is susceptible to weld failure.
A second known mounting bracket uses multiple vertical struts secured to the axle housing by vertical welds. The welds holding the struts to the housing, while located in the vicinity of the housing's neutral axis, each have a beginning and an end which act as stress risers making the weld susceptible to failure. Of course, when the attaching welds fail at an extreme point along their length, reduced weld areas transmitting the same force result in increased stress levels which, in turn, induce further failure in the remaining, intact welds. Through this mechanism, cracks in welds propagate over time. It has been determined that welding on the top and bottom of an axle housing is undesirable due to the extent of flexure at and the high stress levels experienced in the extreme fibers of the housing relative to its neutral axis. It has also been determined that welds which hold the mounting bracket to the axle housing and which are subjected to high stresses should be configured along a smooth arc or radius.
U.S. Pat. No. 4,134,507 discloses a flexing beam on which is mounted a bracket having an opening through it and a weld seam arranged around the periphery of the opening between the flexing beam and bracket about the beam's neutral axis. U.S. Pat. No. 1,293,872 illustrates two conduits joined together by abutment within a surrounding sleeve and subsequent welding through the sleeve to each of the attached conduit ends. While the aforementioned U.S. patents illustrate welding about the periphery of an opening, they do not relate to optimum disposition of the components of axle housing mounting brackets nor how or where the mounting brackets and axle housings are interconnected.
Accordingly, the present invention is intended to overcome the deficiencies of the known, aforementioned mounting brackets.